1. Field of the Invention
The present invention relates generally to a hand tool, and more particularly to an adjustable wrench, which has can secure the movable jaw when it moved to a predetermined position.
2. Description of the Related Art
A conventional adjustable wrench comprised a handle having a fixed jaw at an end thereof, a movable jaw slidably provided on the handle having a rack and an adjusting worm pivoted on the handle and engaged with the rack of the movable jaw such that the movable jaw can be moved by turning the adjusting worm.
There must be a clearance of teeth left between the rack of the movable jaw and a helical tooth of the adjusting worm to make the adjusting worm can drive the movable jaw to move smoothly. But the movable jaw can not stand fixedly because of the clearance of teeth such that the distance between the movable jaw and the fixed jaw can not be kept in a same size, even through the adjusting worm had not been turned.
FIG. 12 shows a conventional apparatus for an adjustable wrench to secure a movable jaw 78. The adjustable wrench has a hole 74 on a handle 72 and a fastening device 76 provided in the hole 74. The fastening device 76 can be screwed into the hole 74 and press the movable jaw 78 to secure the movable jaw.
FIG. 13 shows a second conventional adjustable wrench having a screw bar 82 driven by a nut 80 to press a movable jaw 84.
FIG. 14 shows a third conventional adjustable wrench having a rectangular slide 86 sliding transversely and against a worm 88 to make the worm 88 can not be turned.
FIG. 15 shows a fourth conventional adjustable wrench having a movable plate 90 with teeth 90 thereon engaged with clutch teeth 96 at a movable jaw 94.
FIG. 16 shows a fifth conventional adjustable wrench having a locking disk 98 to secure a adjusting worm 100.
FIG. 17 shows a sixth conventional adjustable wrench having a control mechanism 102 to move a worm 104 and make the worm against a movable jaw 106.